Well i guess it depends on how technical you want to get. You can play games from a networked computer on the Wii. just not Wii games. There are emulators that let you connect to a SMB share to get the games. With how small the old nintendo games are it probably is not streaming though. Just holding the entire game in memory i would imagine. Any extra details on this would be good to hear if anyone knows. If they do actually stream as you play or if it is just downloaded and held in memory?

This was done on a console/handheld, it was done on the PSP, you could choose to stream via USB or Wifi, although USB was faster,
and imagine this, you could even then open the streaming port and if ballsy enough you could then try to stream
from off the LAN :P, I think I was able to stream some games off the LAN but those were smaller simple games.

As to how it worked, idk if it copied/cached a version onto the PSP, but I think it actually acted as a direct IO to the stream, so it was real streaming, but I think it also cached some parts locally after being streamed.

I know I was able to play FF Crysis Core (~1GB) over streaming on the PSP, the loading screens may have taken longer? but it definitely worked
but see maybe PSP's because they have smaller memory would be able to Directly ask the IO over the network what it needed to load into the memory and then once in the memory it doesn't need any IO until the next load, which would be why lots of games on the PSP have plenty of loading points.
It's then quite possible that a Wii would load when it needs to and accesses the IO much more frequently, but still it should have most loaded into the memory and then cached which cuts down on the IO to the disk/backup/stream

So I'm guessing nothing exists, but it would be crazy awesome to see someone at least try, I mean there's Wii games that are only 300-700 MBs and if I PSP can do it, why couldn't the Wii? I would almost settle for a temp download, but most games would then take like 10 minutes in wait to even play : ( when copied over wifi, but if it coudl stream.... you'd be sitting awesome

Okay I think you guys are talking about 2 different things (or I am missing the point entirely)

1. Transferring/Copying backups to an HDD and playing as normal from the External device attached to the Wii.

2. Streaming the Games and playing them on the wii.

These are totally different.

1. Yes it should be possible....but why???

2. Not possible for any gaming console as of right now.

Well I will not go into much detail on how wrong you are , but the gamecube has had this for years. You could stream any game from your computers shared network hdd and play it on your Gamecube. No disk no hdd plugged into the Gamecube. All game data from your network. The app is called "Paradox GC Disc Server". The psp can stream also.